Scientists consider termites to be a branch of the cockroaches that developed a social lifestyle. In the millions of years since they diverged, termites have developed many characteristics that differentiate them from cockroaches such as laying eggs singly rather than packaged in an egg case or ootheca. However, the primitive cockroach Mastotermes darwiniensis produces a cockroach type of ootheca and has a many homologies to cockroaches in its reproductive system. Unlike other groups of insects with an external ovipositor, in both cockroaches and these termites, the ovipositor terminates inside the termite in a pouch called the vestibulum. Inside the vesitbulum, the eggs are packaged and coated with secretions. In the past decade, relationships between cockroaches and termites have been confirmed in much greater detail by molecular data.
*C. A. Nalepa and M. Lenz. The ootheca of Mastotermes darwiniensis: Homology with cockroach oothecae. Proc. R. Soc. Lond. B (2000) 267, 1809^1813